Why does rabies cause hydrophobia?

Agony, Hydrophobia and viruses in the light of evolutionary principles

Has hydrophobia been found outside of rabies?

I have only seen it being mentioned as a symptom of rabies.


2 Answers 2


You are correct that hydrophobia is often considered pathognomonic of rabies. However, I offer for your consideration:

Hydrophobia as a rare presentation of Cotard's syndrome: a case report.1

Cotard's syndrome itself is a bizarre psychiatric condition that the authors of the above paper define well:

Cotard’s syndrome is a rare condition where the central symptom is a nihilistic delusion, which, in its complete form, leads the patient to deny his own existence and that of the external world.

The patient described in this case report harbored delusions that his internal organs were shrinking. He asserted that his abdomen would rupture if he internalized anything. The hydrophobia was secondary to this concern. When given a glass of water he showed a panic reaction and attempted to keep away. Orientation and memory remained intact.

The authors go to length to point out that this was not, in fact, a case of rabies (as thought that were in question at this point!). Also, the patient himself was not aware of symptoms of rabies, ruling out "rabies hysteria" (a hypochondriacal delusion that one has rabies).

Hydrophobia, then, is a rare manifestation of a rare psychiatric disease in addition to the more frequent and well-known association with rabies.

1. Nejad AG. Acta Psychiatr Scand. 2002 Aug;106(2):156-8; discussion 158.


Hydrophobia is mostly attributed to rabies, most of the sources refer rabies as hydrophobia. Technically Hydrophobia is the intense fear of water.

Hydrophobia is an intense, irrational fear of water that can be commonly diagnosed at childhood and should be treated as soon as possible. Certain types of hydrophobia may also appear in later stages of contracting rabies, which would require treatment on an immediate basis.

Also the Wikipedia link for Rabies states that

Signs and symptoms may soon expand to slight or partial paralysis, anxiety, insomnia, confusion, agitation, abnormal behavior, paranoia, terror, and hallucinations, progressing to delirium. The person may have hydrophobia.

So rabies and hydrophobia are distinct and hydrophobia is a symptom of rabies.

Hydrophobia may, however, more readly be confronted with hysteria, acute mania and tetanus.

Hydrophobia is incidental to other diseases, it can be observed, occassionally, in tetanus,hysteria,cynanche,tonsillaris,tracheitis and certain inflammations in stomach. Tetanus is strongly believed to cause intense hydrophobia conditions.How ever, there is always a belief of hydrophobia linked with rabies.

The pathology of Hydrophobia and Tetanus is found to have great similarities and there is a great similarity in the distribution of lesion in the central nervous system as well as a certain analogy in the kind of lesion. The special localization of symptoms of both disease, in the tongue,throat and neck was associated with the special prevalence of the lesions in the medulla oblongata and especially in the neighborhood of the nuclei in the fourth ventricle etc.

Reference :THE Medical Times and Gazette - J & A Churchill

So it is possible to cause hydrophobic conditions when Tetanus is affected and also hydrophobia can occur from mental disorders.


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